有些反馈信号只影响系统的（），有些反馈信号还对调节系统的不均匀度有影响，反馈愈强，不均匀度愈小。
参考答案：动态特性
述桂枝生姜枳实汤与桔枳姜汤的异同点？
At the railway station, the mother waved goodbye to her daughter until the train was _______.
A．out of sight
B．out of reach
C．out of order
D．out of place
